current in reverse biased p-n junction; independent of bias voltage; depends on concentration of minority carriers and quality of semiconductor.

p-n junction

p-type and n-type semiconductors are brought to contact in order to create a potential barrier; height of the potential barrier is controlled by the voltage applied between p- and n-type regions; in homojunctions p- and n-type regions are formed in the same semiconductor typically by locally changing its doping from p to n, or vice versa; in heterojunctions p- and n-type regions are made out of different semicodnuctors.